Lubricating composition



Patented July 19, 1949 LUBRICATING COMPOSITION 'John P. Buckmann, Redondo Beach, and Loren L. NefLLong Beach, Calif., assignors to Union Oil Company of California, Los Angeles, Calif., a corporation of California No Drawing.

This invention relates to lubricating oil addi tion agents designed to improve the lubricating properties of lubricating oils for use in internal combustion engines. The invention relates particularly to lubricatingoils for use under conditions of severe service such as those encountered in Diesel engines, and the like, and to lubricating oils containing these addition agents.

Primarily, the object of this invention is to produce, for use under such severe service conditions as are encountered in Diesel engines, lubricating oils which will be non-corrosive to corrosion-sensitive bearings, such as the copper-lead or cadmium-silver type, and which willalso avoid the deposition of lacquer and varnish-like materials upon pistons and overcome carbon deposition behind the rings. Such oils are said to have detergent and anticorrosion properties.

Other objects of this invention will be apparent from the description contained hereinafter.

It is well known that ordinary mineral lubricants are effective only within certainlimits of engine operating conditions and when these limits are exceeded deterioration of the lubricating oils results causing undesirable ring sticking,

bearing corrosion, sludge formation, piston lacquering, and the like. Addition agents have been developed and used in lubricating oils to minimize this deterioration and to reduce its deleterious efiects if it does occur.

Addition agents which have been proposed for the improvement of lubricating properties of lubricating oils are many in number. In general these agents are designed to function in some specific manner; for example, an addition agent to which is attributed detergent properties is one which tends to keep pistons, rings and valves free of lacquer and varnish-like deposits. Such addition agents are known in the trade as detergents. Oil-soluble metal salts of sulfonic acids are perhaps the most used addition agents to improve the detergent properties of a lubricating oil and their use is well known in the art. Prevention of bearing corrosion is another specific function for which lubricating oil addition agents have been designed. Addition agents, known as anticorrosion' agents, which perform this function include phenolic compounds, metal salts of the reaction products of a sulfide of phosphorus and an alcohol, metal salts of the reaction products of a sulfide of phosphorus and a hydrocarbon, such as those disclosed in U. S. Patent 2,316,082 to Loane et al., and many others. 7

Application December 20, 1946, SerialoNo. 717,616

14' Claims. (Cl. 25232.7)

The present invention resides in lubricating phorus and a particular hydrocarbon fraction,

to be described hereinafter, obtained in the refining of lubricating oils. The invention also resides in lubricating oils, preferably mineral lubricating oils, containing oil-soluble metal salts of the reaction products of sulfides or oxides of phosphorus and a hydrocarbon fraction together with oil-soluble metal salts of sulfonic acids, phenols, the reaction'product of phosphorus pentasulfide and an alcohol, the reaction product of phosphorus pentasulfide and a phenol, synthetic organic acids prepared by oxidizing high molecular weight mineral oil and paraffin wax fractions and the reaction product of phosphorus pentasulfide and a long chain olefine hydrocarbon.

We have discovered that the performance of internal combustion engines under severe service conditions such as those encountered in Diesel engines can be markedly improved by the use of a lubricating oil to which have been added small amounts of an oil-soluble metal salt of the reaction product of a sulfide or oxide of phosphorus with the particular hydrocarbon fraction referred to above.

We have also discovered that the lubricating properties of a lubricating oil can be markedly improved by the addition of these same small quantities of an oil-soluble metal salt of the reaction product of a sulfide or oxide of phosphorus and a hydrocarbon or hydrocarbon fraction to-- gether with small quantities of an oil-soluble metal salt of a sulfonic acid or small quantities of other phosphorus containing addition agents such as oilsoluble metal salts of reaction products of a sulfide of phosphorus with a long chain olefin hydrocarbon, alcohol or phenol.

Not only may an oil-soluble metal salt of the reaction product of a sulfide of phosphorus and a hydrocarbon fraction be used in conjunction with an oil-soluble metal salt of a sulfonic acid as described hereabove, but it may also be used in conjunction with other lubricating oil addition agents such as detergents or anticorrosion agents. Such other detergent addition agents which may be used in conjunction with the oilsoluble metal salt of the reaction product of a phosphorus sulfide or oxide and a hydrocarbon fraction include oil-soluble metal salts of fatty 3 acids, halogenated fatty acids or substituted fatty acids such as dichlorostearic acid, phenyl stearic acid and the like; oil-soluble metal salts or soap of rosin acids such as abietio acid, hydrogenated rosin acids and the like; oil-soluble metal salts or soaps of acids produced by oxidizing hydrocarbons or hydrocarbon fractions such as paraffin wax, parafiinic lubricating oil fractions and the like; oil-soluble metal salts of phosphonic or phosphinic acids obtained by reacting elemental phosphorus with hydrocarbons as described in U. S. Patent 2,311,305 to Ritchey; and oilsoluble metal salts of reaction products of sulfides of phosphorus with long chain olefin hydrocarbons; and many others. Anticorrosion. agents which may be used in conjunction with the oil-soluble metal salt of th reaction product of a phosphorus sulfide or oxide and a hydrocarbon fraction include oil-soluble metal salts of phenols and particularly alkyl or cycloalkyl sub- L stituted phenols such as those having more than about 12 carbon atoms per molecule; oil-soluble metal salts of phenol sulfides or alkyl or cycloalkyl substituted phenol sulfides and particularly those having alkyl substituents containing at least about 4 carbon atoms; oil-soluble metal salts of the reaction products formed by reacting a sulfide or oxide of phosphorus with an alcohol or with a phenol; and many others.

We have discovered further that not only does the combination of an oil-soluble metal salt of the reaction product of a phosphorus sulfide and/or oxide and a hydrocarbon with one of the other agents mentioned improve the lubricating qualities of a lubricating oil, but that any of these indicated combinations may be used in conjunction with a third lubricating oil addition agent which may be any one of those described as the second component of our combination addition agent to impart specific desirable properties to lubricating oils.

The oil-soluble metal salt of the reaction product of a sulfide of phosphorus and a hydrocarbon to be used in the practice of our invention is generally prepared by first reacting a sulfide or oxide of phosphorus with a hydrocarbon or hydrocarbon fraction and then preparing a metal salt of the reaction product. Thus a phosphorus sulfide or oxide, preferably phosphorus pentasulfide,

in amounts in the order of about 3% to 50%, preferably 10% to 20%, by Weight of the hydrocarbon used is reacted with a hydrocarbon such as naphthalene, acenaphthene, lauryl benzene ,or. the like or with a petroleum fraction such as one described herein below, for one to twelve hours at temperatures of about 200 F. to 690 F., preferably at about 400 F. This reaction, when carried out with a sulfide of phosphorus, proceeds with the evolution of hydrogen sulfide and is generally continued until such evolution ceases. Moreover, it has been observed that when the reaction is effected with phosphorus pentasulfide elemental sulfur is sometimes one of the reaction products. When phosphorus pentoxi'd'e is employed water is one of the reaction products.

The reaction product is acidic and capable of forming salts with basically reacting compounds. Salts may be prepared directly from the crude reaction product or the reaction mixture may first be blown with nitrogen, fuel gas, steam or other gas to remove volatile reaction products from the mass. The desired: oil-soluble metal salt is usually prepared by direct neutralization of the above reaction mixture with a basic compound of the desired metal such as the oxide; hydroxide or carbonate, but it may also be prepared by first neutralizing the reaction mixture with a hydroxide .or oxide of an alkali metal, such as sodium or potassium, and then preparing the desired metal salt from the alkali metal salt by metathesis. For example, a heavy metal salt, such as the nickel salt, may ?be prepared by metathesizing the sodium salt of the'reaction product with a nickel salt using conditions well known in the art for efiecting reactions of this type. When direct neutralization. of the reaction mixture with a metal hydroxide, .oxide, or carbonate is carried out it is sometimes: advantageous to dilute the reaction mixture with about an equal volume of a lower boiling hydrocarbon or hydrocarbon fraction such as a low boiling gasoline or naphtha traction or and to use a small amount of water along with the metal hydroxide, oxide, or

carbonate. Under such conditions and particularly if slightly elevated temperatures are employed, the neutralization proceeds to completion in a rather short period of time.

When a sulfide-of phosphorus is reacted with a hydrocarbon orhydrocarbon fraction as described above and an oil-soluble metal salt .of the reaction product prepared, it is found that the atomic ratio of phosphorus to sulfur in the product is generally within thelimits of about 0.5 to about 1.5. It is believed that the atomic ratio of phosphorus to sulfur exhibited by the product is a contributing factor to the performance of oils containing this product although the reasons are not entirely clear.

Phosphorus sulfides .or oxides which may be employed include phosphorus pentasulfide, phosphorus trisulfide, phosphorus pentoxide and phosphorus trioxide as well as other sulfides or oxides of phosphorus and mixtures of these sulfides and/or oxides. In place of phosphorus sulfides and oxides we may employ mixtures of elemental phosphorus and elemental sulfur as reaction agents. Incarrying out the reaction between a hydrocarbon or hydrocarbon fraction and phosphorus and sulfur, white phosphorus and powderedsulfur are added to the hydrocarbon or hydrocarbon fraction and the mixture is heated toat least about 300 F. and preferably to at least about 490 F1 fora period of 2 hours or until the reaction complete. The reaction product is then treated in the manner described for treatment of the product obtained when a sulfide or oxide of phosphorus'is reacted with a hydrocarbon or hydrocarbon fraction.

In the following description the term phosphosulfurization will be employed to indicate the reaction between-a phosphorus-sulfide, a phosphorus: oxide or phosphorus and sulfur with a hydrocarbon. The reaction product will be described generically as an acid ofphosphorus having an organic subs-tituent. More specifically, the product obtained by reacting a hydrocarbon with a phosphorus sulfide will be designated as a sulfur-containing acid of phosphorus having an organic substituent;

Although many'hydrocarbons and hydrocarbon fractions-may be used in the preparation of acidic phosphorus compounds by treatment with phosphorus sulfides or oxides, there appear to be great differences in their reactivity, i'. e., in the ability of the hydrocarbons or hydrocarbon fractions to form the desired phosphorus compounds. Thus, although petroleum distillates boiling in the 111-- bricating oil range may generally be employed as the phosphosulfurization stock, the yields ,of the desired acidic products are usually low and theproducts are contaminated with undesirable poly merized or resinified bodies which are. objection: able and which are difiicultly separable from the desired reaction products. distillates boiling in the range'of gasolines, kerosenes and spray oils and portions of these dis-'- tillates obtained from them by distillation, solvent extraction and the like may also be reacted with phosphorus sulfides or oxides to produce acidic phosphorus containing materials, but here again the yields of the desired oil-soluble products are low and the reaction is accompanied by the formation of many undesirable resinous or polymerized bodies. Y

We have found that by various means de- Similarly, petroleum 6 vary with the type of stock employed and with the efliciency of the solvent fractionation used to produce it. Although the physical characteristics of the desired intermediate fraction will I vary with the type of crude oil from which it has i been produced and with the viscosity of the fraction extracted, in general, the viscosity gravity jfand Coates in the 'Journal of Industrial and} constant is a relationship between the viscosity and gravity of an oil and is'describedby Hill Engineering Chemistry, vol. (1928) page .641.

- ,The limits indicated are not the limits for the scribed herebelow it is possible to separate from lubricating oil fractions of petroleum, such as lubricating oil distillates, fractions which phosphosulfurize readily to produce relatively high yields ,of the desired reaction productswithout the formation'of the undesirable polymerized or resinified materials described above. The preferred fraction is one which contains hydrocarbons that are not highly paraflinic and yet not highly aromatic. Thus it is desirably one obtained as an intermediate fraction or heart cut from a lubricating oil distillate by fractionation of the lubricating oil distillate with a selective solvent.

It is to be understood that the'term selective solvent refers to a solvent such as phenol, furfural, nitrobenzene, dichloroethyl ether, sulfur dioxidebenzene, benzonitrile, benzaldehyde, chloroaniline, chlorophenol, and the like, by means of which it is possible to fractionate mineral oil fractions on the basis of the relative parafilnicity or aromaticity of the molecules present. Thus these solvents selectively dissolve the more aromatic hydrocarbon molecules leaving the more parafiinic molecules undissolved. By controlling the amounts of solvent and other conditions of extraction such as temperature it is possible to control the proportion of any given stock which will be dissolved. The term selective solvent is to be distinguished from the general term solvent for the latter includes such materials as propane, isobutyl alcohol, n-propyl alcohol, methyl acetate, acetone and others which are known to be solvents for petroleum fractions, but which do not show selectivity. That is, materials of this latter typeare not capableof separating a petroleum fraction on the basis of the parafiinicity or aromaticity of the molecules present. The V question of selectivity of solvents has been discussed by Ferris, Birkhimer and Henderson in the Journal of Industrial and Engineering Chemistry, vol..23 (1931), page 753.

By the use of a selective solvent in two extraction. steps it is possible to separate a lubricating oil fraction into three fractions, i. e., a first extract, a second extract and a final raffinate, In this case the first extract would comprise the most highly aromatic molecules, the final raflinate would comprise the most highly parafilnic molecules and the second extractwould comprise molecules which are more aromatic than the,

molecules present in the raffinate but less aromatic. and thus more paraffinic than the molecules present in the first extract. Such a material, i. e., the second extract would constitute a desirable phosphosulfurization stock. Such a fraction may be obtained from substantiallyany lubricating oil .stock whether obtained from naphthene or paraflin type crude oil, but the amount of the desired fraction obtainable will;-

average 'V. G. C; of the fraction but rather they represent the practical limits of the V. G. C.s of the molecules present in the desired fraction. Under any circumstance the desirable fraction will not contain more than about 20% by volume of material having V. G. C.s outside of the range of 0.82 to 0.95. The presence of undesirable material may be determined by a solvent fractionation involving two or more solvent extractions with a selective solvent. Thus, extraction of the particular fraction under conditions such that 5% to 10% of the fraction will be removed as extract should produce an extract oil having a V. G. 0. not greater than about 0.95. Furthermore, extraction with a selective solvent which will dissolve to of the fraction should leave 5% to 10% of a rafllnate oil having a V. G. C. not less than about 0.82.

In preparing a particularly desirably phosphosulfurization stock, a lubricating oil fraction of a waxy Santa Fe Springs (California) crude oil was prepared by vacuum distillation in the presence of superheated steam. This distillate was dewaxed by diluting with 4 volumes of liquid propane, cooling to --50 F, and filtering to remove the wax. The propane was then removed by a topping distillation. The results of tests on the waxy distillate and on the dewaxed distillate were as follows:

The dewaxed distillate was extracted with 3' volumes of phenol at F, to produce, after removal of the phenol, a phenol raflinate and a phenol extract. This phenol extract amounted to about 55% by volume, and the phenol raflinate amounted to about 45% by volume, of the dewaxed distillate. The phenol extract was further treated with 7 volumes of furfural at 150 F. to produce, after removal of the furfural, a furfural raflinate and furfural extract. The furfural raffinate amounted to about 35% by volume of the phenol extract or about 19% by volume of the dewaxed distillate. This furfural rafiinate is a particularly desirable hydrocarbon fraction for reacting with a phosphorus sulfide or oxide to produce our lubricating oil blending agents.

The characteristics of this furfural rafiinate fraction are given below together with the char:-

armada aeteristics of the phenol ralfina'te, phenol extract and'furfuralextract. 1

ins conditions oi extraction, temperature, solvent ratio, etc, in such a manner that the desired hy- Phcnol Phenol Furfural Furiural Raifinste Extract Ralfimte 7 Extract Gravity, API 28.7 19. 7 Viscosity, SUS at- I I 1085 F Q. v 729 1 110,000 3, 800 v1 400,000 1 130 F 305 12,354 87, 197 210 F 73.1 394 131- 919 Gonra'dson carbon, perce residue- 0. 03 2. 9 1. 4 5. 8 Iodine No. (Hanus), Mg. Iodine absorbed p 0. 62 3.1 1.2 24.4 Sulfur, percent 1.04 0. 97' 1.05 Carbon, percent 86'. 87.57 J 85; 86. 82 Hydrogen, percent l l. 1'4. ll 10. 87 '12 33 9.93 Viscosity Index. -270 28. 9 -82() Viscosity gravity constant based on viscosity at 210 F.- 0. 806 0. 864

i Extrapolated The prel'erred hydrocarbon fraction to be used in the practice of our invention may also be prepared in other ways, For example, the above described procedure may be modified to obtain the desired material. Instead of re-extracting the phenol extract with furfural the solution of phenol extract'in phenoi or the original phenol extract phase-maybe cooled until the desired raffinate has separated or sufficient quantity or water may be added to the extract phase to release or reject the desired proportion of raffinate. Also a lower boiling hydrocarbon, such as propane, butane, ,a light gasoline or naphtha fraction, or the like, may be added to the phenol extract phase to effect the separation of the desired rafiinate. One modification oi the above described procedure which has been employed to obtain a desirable phosphosulfurization stock involves a combination of treatments. Thus, the phenol extract phase was separated from the phenol rafiinate phase and treated with a small amount, in the order of 1% to 6 by volume, of water at a temperature of 140 F. to cause the rejection of the more paraffini-c; molecules present in the extract phase. This suitable phosphosul furization stock, designatedas reject oilfhad' a viscosity gravity constant of 0.941.

It is also possible to produce the same desirable material by using other selective solvents at any or all stages of the process as outlined drocarbon fraction will be obtained as extract from the first raflinate.

The desirability of employing an intermediate fraction of a lubricating oil distillate which is separated from the lubricating distillate by a solvent fractionation process. is illustrated by the results of phosphosulfurization reactions which have been carried out on the various fractions described above which were prepared by first extracting a lubricating distillate with phenol and subsequently extracting the extract oil from" the phenol extraction with furfural. Thus'the' phosphosulfurization reaction was carried out on the phenol raffinate, the'phenol extract and on the furfural raffinate from the extraction of the phenol extract as well as on the furfural extract. In each case the hydrocarbon fraction was heated {or three hours at about 406 F. with; 12.5% by weight of phosphorus pentasulfide. The reaction product was diluted with three volumes: of a parafiinic solvent havin a boiling range of about 140 F, to about 200 F. and consisting pri-' marily of hexanes and heptanes, the diluted material was filtered to remove insoluble reaction products and the filtrate reacted with an excess: of lime, the excess being removed by filtration after neutralization was complete. The filtered product was, evaporated to remove the, solvent,' The yields of oil-soluble products and the percentagesof phosphorus, sulfur and calcium in a second above in place of phenol and furfural. Thus, the various products are shown below:

Dewaxcd Phenol P1181101 Furfural Furiural Distillate Raifinate Extract Rafiinate Extract 1 Yield of oil-soluble reaction product, based on total reactants, per cent by weight 85 91 80 95 74j Phosphorus content of oil-soluble product, per cent by weight 0.9 0. 2 l. 67 2. 39 1. 48 Sulfur when of oil-soluble product, per cent by Weight l. 1. 7 0. 4 3. 50 4, 08 3. 30 Calcium content of oil-soluble product, per cent by weight 0. 9 0.2 0. 89 2. 29 0. SQ

the first extraction may be carried out with phenol, furfural, sulfur dioxidebenzene, nitrobenzene, or some other suitable solvent and the second extraction carried out with the same solvent under different conditions of temperature, solvent ratio, etc. or with a difierent solvent suitable for effecting the separation of the desired material. j

' Among other methods of preparing the desired material which will be obvious to those skilled in the art, may be mentioned that of changing the solvent and/or conditions of extraction in such a manner that the desired material will be found in the first rafiinate fraction rather than the extract fraction. A second extraction may then be performed on the raiiinate from the first p The lower yields of oil-soluble reaction products obtained with the phenol extract and with the furfural extract are due to the production of appreciable quantities; i. e.', about 20% and about" 30%, respectively, of polymerized material which is insoluble in the solvent employed and in lubri-' l cating oil. The desirability 'of hydrocarbon ma-- teri'al'for phosphosulfurization depends not alone upon the high yields of oil 'soluble reactions produced, but also upon the phosphorus, sulfur andmetal content of the final reaction product; Thus, phenol raflinate gives a relatively high yield of oil-soluble product, however, very little phos phosulfurization occurs as indicated by the low'. phosphorus, sulfur and metal contents. The phosphosulfuriaed' product or the product" extraction using any suitable solvent and adjustobta ne aft r're ins a hydr r on or hydro-1 carbon fraction with a sulfide or an oxide of phosphorus will be referred to herein as a concentrate. Such concentrates may contain, depending upon the reactivity of the hydrocarbon or hydrocarbon fraction, upon the amount of phosphorus, sulfide, or oxide employed and upon the conditions of reaction, between about .05% and about 5.0% by weight of phosphorus in the form of an oil-soluble reaction product. These concentrates after neutralization with lime or other metal oxide or hydroxide may be added to lubricating oils in amounts sufficient to produce oils containing the desired proportions of reaction product as determined by their phosphorus content. When these additives are employed as the only addition agents, the final oil will desirably contain between about 0.01% and about 0.5% by weight of phosphorus and preferably between about 0.05% and about.0.2% by weight of phosphorus.

In preparing lubricating oils containing the reaction product of a phosphorus sulfide or oxide other phosphorus containing materials are'present thephosphorus' content of the finished oil due to the presence of said phophorus containing materials will be between about 0.005 by weight and about 0.5% by weight and preferably between about 0.02% by weight and about 0.2% by weight.

If the auxiliary addition agent is not a phosphorus containing material it will constitute between about 0.1% and about 5.0% by weight and preferably between about 0.5% and 2.5% by. weight of the finished oil.

The amount of phosphorus contained in these oils was determined by a standard analytical procedure consisting of first converting the phosphorus in a weighed quantity of the material to beanalyzed to the phosphate form by oxidation with sodium peroxide ina Parr bomb and then finishing the analysis according to the procedure given by Kolthoff and Sandell, Textbook of Inorganic Analysis (1936), page 676, for the determination of phosphorus in steel. wherein the phosphorus is weighed as magnesium pyrophosphate.

Suitable oil-soluble phosphorus containing materials which may be employed in conjunction with the lubricating oil addition agent of the presv.-

ent invention may be prepared by reacting a sulfide of phosphorus with a long chain olefin hydrocarbon preferably of at least 12 carbon atoms and converting the reaction product to a metal salt.

Examples of such olefin hydrocarbons are cetene,

ployed are olefin polymers obtained by the action of such agents as aluminum chloride, hydrogen fluoride, boron fluoride and the like upon olefin hydrocarbons such as ethylene, propylene, butylene, octene, dodecene, octadecene and the like under conditions which are well known in the art.

Such olefin polymers may have molecular weights above about 500 and preferably below 20,000.

Thus an oil-soluble phosphorus and sulfur containing material may be prepared from a polymer of isobutylene and phosphorus pentasulfide. A polymer of isobutylene having a molecular weight of about1500 is reacted with 10% by weight of phosphorus pentasulfide at a temperature ofapproximately 390 F. for a period of about 5 hours. The reaction mixture is then cooled to approximately F., diluted with an equal volume of an SAE 20 mineral lubricating oil and 5% by weight of potassium hydroxide is added. The temperature of the mixture is gradually raised to about 350 F. over a period of about 2 hours and then maintained at this value for a period of three additional hours. This product is suitable for use in the present invention. If desired the odor of the product may be improved by steam or nitrogen stripping at an elevated temperature such asapproximately 390 F. Such a stripping process with steam also serves to increase the atomic ratio of phosphorus to sulfur in the product by decreasing the amount of sulfur but leaving the amount of phosphorus substantially unchanged.

The above and other phosphorus and sulfur containing materials of the type described hereabove which may be employed in the practice of the present inventionare disclosed by Loane et al. in United States Patent 2,316,088.

Other suitable oil-soluble phosphorus containing materials are metal salts of acids produced by the reaction of a phosphorus sulfide or oxide with an alcohol or with a phenol. These materials are preferably those alkyl, aryl, or aralkyl phosphoric or thiophosphoric acid salts prepared by the reaction of P285 or P205 on an alcohol or phenol. The method of preparing these salts is fully described in the Freuler U. S. Patent 2,364,284. The preferred alcohols and phenols are the monohydroxy organic compounds where the organic group comprises an alkyl cycloalkyl, aryl, aralkyl or alkaryl radical. Not only may these oil-soluble salts of reaction products of a sulfide or oxide of phosphorus and an alcohol or phenol be employed in conjunction with our reaction product of a sulfide or oxide of phosphorus and a hydrocarbon fraction with beneficial results but they are also found to produce excellent lubricants when used in a lubricating oil in conjunction with the metal salts of phosphorus containing materials prepared by reacting a sulfide of phosphorus with a long chain olefin hydrocarbon as described hereabove.

Oil-soluble sulfonates' which may be used in conjunction with our reaction product between an oxide or sulfide of phosphorus and a hydrocarbon include the metal salts of substantially any oil-soluble sulfonic acid. Suitable sulfonic acids are obtainable on the market, generally in the formof their sOdium salts, containing about 50% by weight of sodium sulfonates and 40% by weight of mineral oil. The sodium salts may be used directly or they may be converted into other metal salts by processes of metathesis which are well known in the art. 7

If desired the oil-soluble metal salt of a sulfonic acid may be prepared by direct sulfonation of a suitable material, with fuming sulfuric acid, gaseous sulfur trioxide, chlorosulfonic acid, etc, to form oil-soluble sulfonic acids followed by the preparation of metal salts either by direct neutralization with a basis metal compound, such as the dioxide, hydroxide or carbonate, or by neutralization with a metal oxide, hydroxide or car'- 11 bonate followed by preparation of the desired metal salt bymetathesis. The petroleum fraction described above as furfural ramnate is of particular value as a starting material for the preparation of oil-soluble metl salts of sulionic acids because this stock appears to yield i quantities of desirable oil-soluble .sulfonic acids. The type of sulfonic acids which are preferably employed are those commonly described as mahogany acids as distinguished from the green acids which are the water soluble sulfonlc'acids produced along with the mahogany acids in the sulfonation of petroleum fractions. Although the mahogany acids are the preferred sulfonic acids "from which oil-soluble metal salts are produced it is known that relatively large proportions of green acid salts may be solubilized in a mineral oil by the oil-soluble mahogany acid salts and such mixtures of mahogany sulfonates and green sulfonates, the latter solubilized by the mahogany sulfonates, may be employed in our lubricating compositions.

Oil-soluble metal salts of phenols which may be used in the practice of our invention include the oil-soluble metal salts of many phenolic materials such as those of alkyl or cycloalkyl substituted phenols having more than about 12 carbon atoms per molecule as well as phenol sulfides of the alkyl hydroxy phenyl thio other type. Thus metal phenates such as those described in U. S. Patent 2,281,401 to Wilson and 'U. S. Patent 2,344,988 to Kavanagh et al., may be employed. Phenol sulfides of the above type which may be employed are described in U. S. Patent 2,139,766 to Mikeska et a1. and similar compounds together with their method of preparation are described in U. S. Patent 2,139,321 to Milzeska et al. Suitable oil-soluble metal salts of synthetic organic acids produced by oxidizing hydrocarbons or hydrocarbon fractions are described in U. S. Patent 2,270,620 to Bray. Thesynthetic organic acids used in the preparation of oil-soluble metal salts are preferably obtained by oxidizing relatively high molecular weight hydrocarbon fractions such as highly paraifinic lubricating oil fractions and the like or parafiin wax. The acids so produced may be converted into the metal salts directly or they may be chlorinated and the chlorinated acids converted into their metal salts.

12 the desired range. We may also add the desired quantities of one or more of the lubricating oil additives described herein to the above composition to impart other and additional specific and I desirable properties to the finished composition.

' The metal salts employed are oil-soluble and require only simple mixing with a lubricating oil to obtain solution. However, the blending is usually effected at slightly elevated temperatures in the range of 100 to 200 F. in order to facilitate solution and dispersion of the addition agents in the body of the lubricating oil.

Methods which have been employed to evaluate lubricating compositions of our invention include various accelerated engine tests. These tests have been run on oils without the addition of our agents and on oils containing our addition agents.

Three diiierent engine tests have been employed in the evaluation of our lubricating oils. These tests have been carried out in 'Lauson single cylinder engines, standard 6 cylinder Chevrolet engines and a single cylinder Caterpillar Diesel standard test engine. The tests are referred to as the Lauson engine test, the Chevrolet engine test and the Caterpillar test, respectively, and are commonly used in the industry to evaluate 111- bricating oils.

In carrying out the ,Lauson engine test, the englue is operated .for a total of fillhours under a load of about 3.5 horsepower with. a' coolant temperature of about 295 F. and an oil temperature of about 280 F. This test is employed to determine the lacquering and corrosion tendencies of the oil. At the end of the-test the cleanliness of the engine is observed and given a, numerical detergency rating between 0 and 100%, Where 100% indicates a perfectly clean engine. Thus a detergency rating of 100 would indicate that there were substantially no lacquer or varnish-like deposits Within the engine. The corrosivity of the oil is measured by determining the loss in weight of corrosion sensitive copper-lead bearings after 20, 40 and '60 hours of operation. In some instances the corros'ivity is also determined by measuring the loss in weight of .a lead strip suspended in the oil in the crank case of the engine. In those cases in which corrosion was extremely severe and there appeared to be danger of engine Preferably the acids will contain in excess of 11) failure due to excessive corrosion of the coppercarbon atoms per molecule.

Metals which may be used to form the desired metal salts or soaps of each of the additive materials described hereinabove include alkali metals such as sodium, potassium and lithium, the alkaline earth metals such as calcium, strontium, barium and magnesium, and the 'polyvalent metals such as zinc, nickel, aluminum, lead, manganese, mercury, cooper, iron, tin, chromium, bismuth and thorium.

The products of this invention may be employed to improve the lubricating qualities of any lubricating oil, but we prefer to use mineral lubrieating oils, especially mineral lubricating oils having a viscosity index (defined by Dean and Davis, Chemical and Metallurgical Engineering, {701. 36, page 618 (1929)) in the range of about '75 to about 95, such as those produced by solvent treating parafiinic base stocks.

In preparing high quality lubricating compositions we may add to a lubricating oil a sufiicient quantity of the metal salts of the reaction product obtained by reacting phosphorus oxide or sulfide with a hydrocarbon to impart to the in weight of copper-lead bearings is determined after 35 hours of operation.

In the" Caterpillar test which is employed to determine the detergency of an oil, 1. e., the ability of the oil to prevent lacquering of the engine, the engine is operated for a period-of .100 hours under a load of about 19.8 horsepower with a coolant temperature of about 175 F. and an oil temperature of about 145 F. At the end of the testa numerical Detergency rating is assigned. The method of rating is similar to that employed in the Lauson engine test and 100% indicates a completely clean engine;

The following specific examples are given to finished lubricating oil a phosphorus content in" further illustrate our invention, however, they with a few milliliters of water. was neutral it was filtered to remove the excess ,unreacted Ca(OH)2; the solvent was then removed from the filtrate by evaporation on a steam should not be taken as limiting the broad aspects 2 of our invention.

Example I To 1170- grams of the petroleum fraction de- 4 about 400 F. During the early stages of the reaction evolution of hydrogen sulfide was vigorous, but at the end of the reaction period evolution of hydrogen sulfide had practically ceased. The

mixture was cooled to room temperature, diluted with about an equal volume of a light paraflinic hydrocarbon solvent having a boiling range of 140 F. to 200 F. and filtered. About one-third of the filtrate was heated on a steam bath to about 60 C. and an excess of Ca(O-H)z added along When the mixture bath followed by heating to about 140 F. under a vacuum of about inches of mercury. The

evaporated product amounting to 484 grams contained 4.08% sulfur, 2.39% phosphorus and 2.29%

calcium. This material will be designated here- 'inafter as product A.

The efficacy of product A in preventing deposition of lacquer and varnish-like materials upon the piston and behindthe rings of an internal combustion engine and in preventing corrosion of alloy bearings of the copper-lead typewas shown by dissolving 6.7% by weight of the material in a mineral lubricating oil of SAE grade having a gravity of 28.5" API, a viscosity of 746 SSU at 100 F. and a viscosity index of 90 and {evaluating the solution for its lubricating properties in the Lauson engine test.

(Du-Pb bearing replaced by babbitt hearing at 40 hrs. due to excessive corrosion.

Example II A 1000 gram portion of the petroleum fraction described hereinabove as furfural raffinate was diluted with two volumes of a petroleum naphtha fraction having a boiling range ofabout 200 F. to about 300 F. and sulfonated by treatment with 333 ml. of fuming sulfuric acid in a vessel equipped with a continuous stirrer and a ther; mometer. The fuming sulfuric acid was added at such a rate that the maximum temperature attained during the sulfonation was about F. As soon as all of the fuming sulfuric acid had been added the reaction mixture was stirred into three liters of the same solvent and allowed to stand over night. The solvent solution of the oil-soluble sulfonic acids was then separated from the acid sludge layer by decantation and the acid sludge layer washed free of oil-soluble sulfonic acids by repeated washings with solvent.

The combined'original naphtha solution and washings were blown with fuel gas at room temperature to remove S02 and an excess of Ca(OH) 2 was added along with a small amount of water. When neutralization was complete the mixture was dehydrated by topping to 260 F. on a hot plate and the unreacted Ca(OI-I)z filtered ofl using finely ground diatomaceous earth as a filter aid. The naphtha was removed from the filtrate by topping to 00 F. and 644 grams of a calcium sulfonate concentrate were obtained.

This material will be designated hereinafter as product B. The calcium sulfate ash value of product B was about 4.0%; this being the value obtained by heating a weighed sample of the calcium sulfonate concentrate to be tested, in the presence of sulfuric acid, to obtain a residual ash of calcium sulfate, and expressing the result in terms of per cent by weight of the concentrate tested.

A Lauson engine test was made on a lubricating oil consisting of 7.4% product B, 3.3% product A and 89.3% of the mineral lubricating oil described in Example I. The results are shown in the following table:

Cu-Pb bearing replaced by babbitt bearing at 40 hrs. due to excessive corrosion.

Example III A lubricating composition was prepared using as addition agents product A described in Example I and calcium sulfonate prepared from a commercial sodium sulfonate. The calcium sulfonate employed was prepared by diluting the sodium sulfonate with an equal volume of mineral lubricating oil described in Example I and adding to the diluted mixture an excess of cal- .cium chloride. The mixture was heated to about 200 F. and when metathesis was complete the product was dehydrated and filtered. This product, which will be referred to as a calcium sulfonate concentrate, contained about 30% by weight of calcium sulfonates.

A lubricating composition was prepared comprising 6.0% by weight of the calcium sulfonate concentrate, 3.3% by weight of product A and 90.7% by weight of the mineral oil employed in Example I. The resulting oil contained approximately 1.8% by weight of calcium sulfonate, and 0.079% 2y weight ofphosphorus in the form of the calcium salt of phosphosulfurized hydrocarbon. This oil had a sulfate ash of 0.6% by weight.

bearing weight loss determined with the mineral oil containing no additives was 3,000 milligrams. results of the Lauson engine test ou -the lubricating composition are shown in the follow- Cu-Pb bearing replaced by babbitt bearing at 40 hrs. due to excessive corrosion.

Example 11 To 301 grams or the hydrocarbon fraction designated hereinabove as phenol extract was added 37.6 grams of P235 and the mixture was stirred for about three hours at a temperature of about 400 F. The reaction mixture was treated in the manner described in Example I. The yield of oil-soluble product amounted to 269 grams of material having a calcium sulfate ash of about 4.5% and a phosphorus content of 1.67% by weight, This material will be designated hereinafter as product C.

A solution of 6.7% by weight of product C, 6.0% by weight of the calcium sulfonate concentrate described in Example III, and 87.3% by weight of the mineral lubricating oil described in Example I was evaluated as a lubricant in the Lauson engine test. This oil contained about 1.8% by weight of calcium sulfonate and about 0.12% by weight of phosphorus. The results are shown in the following table:

Cu-Pb bearing replaced by babbitt bearing at 40l1rs. due to excessive corrosion.

Example V To 346 grams of the hydrocarbon fraction described hereinabove as furfural extract was added 43.3 grams of ms.- and the mixture was stirred for about three hours at a temperature of about 400 F. The reaction product was treated in the manner described in Example I. The final oilsoluble product amounted to 286 grams of material having a calcium sulfate ash of about 5.0% and a phosphorus content of 1.48% by weight. This material will be designatedhereinafter as product D.

A solution of 6.0% by weight of product D, 6.0% by weight of the calcium sulfonate concentrate described in Example III, and 88.0% by weight 16 of the mineral lubricating oil described in Example I was evaluated as a lubricant in the Lauson engine test. This oil contained about 1.8% by weight of calcium sulfonate and about 0.090% by 1 Cir-Pb bearing replaced by babbitt bearing at 40 hrs. due to excessive corrosion.

Example VI An oil-soluble phosphorus and sulfur containing material was prepared by the reaction of a sulfide of phosphorus upon an olefin hydrocarbon in a manner similar to that described hereinabove. The product, hereinafter referred :to as product E, contained 2.5% phosphorus, 0.9% suland 4.1% potassium.

-An oil-soluble phosphorus and sulfur containing material was prepared by reacting phosphorus pentasulfide with the reject oil petroleum hydrocarbon fraction prepared as described hereina'oo've. The reject oil (2000 grams) was stirred with phosphorus pent-as'ulfide (12.5% by weight) at a temperature of 183-401 F. for a period of 2 hours. The reaction mixture was then diluted with an equal volume of apetroleum naphtha fraction having a boiling range of 200-300" F. and filtered. The filtrate was neutralized with an excess of Ca(OH) 2 by refluxing in the presence of ml. of water and distilling ofi the water through a water trap. The unreacted Ca(OH)2 was filtered ofi and the naphtha fraction recovered by a topping distillation. The topped product, hereinafter referred to as product F, contained 1.4% phosphorus and 1.4% sulfur.

A lubricating composition having a phosphorus content of 0.04% by weight and consisting of 1.6% by weight of product E and 98.4% by weight of the mineral lubricating oil described in Example I was evaluated as a lubricant in the Lauson test. The results are shown in the following table:

I Cir-Pb bearing replaced by babbitt hearing at 40 hours due 'to excessive corrosion.

Example VII A lubricating composition having a phosphorus content of 0.07% by Weight and consisting of 1.6 by weight of product E (contributing 0.04% phosphorus) 2.2% by weight of product F (contributing 0.03% phosphorus) and 96.2 by weight of the mineral lubricating oil described in Example I was evaluated as (a lubricant in the 17 Lauson test. The results are shown in the following table:

1 Oil-Pb bearing replaced by babbitt bearing at 40 hours due to excessive corrosion.

Ermn ple 'VIII A lubricating composition having a phosphorus content of 0.12 by weight and consisting of 1.6% by weight of product E (contributing 0.04% phosphorus), 5.7% by wcightof product F (contributing 0.08% phosphorus) and 92.7% by weight of the mineral lubricating oil described in Example I was evaluated as a lubricant in the Caterpillar test. A detergency rating of 90% was obtained with this lubricant as compared to 50 with the mineral oil without addition agents.

It has been ShOWn that the particular combination of phosphorus and sulfur containing addition agents described above when blended with a lubricating oil yields lubricants having desirable properties. The reasons why the combination functions more satisfactorily than the single agents alone are not clear. The improvement may be due to the use of a monovalent metal salt of materials from long chain olefin hydrocarbons and a polyvalent metal salt of n1aterials from hydrocarbon fractions and it is believed that this is a contributing factor; or the improvement may be due to the fact that materials from long chain olefin hydrocarbons generally exhibit higher phosphorus-sulfur ratios than materials from hydrocarbon fractions. Thus in Example VI above the atomic ratio of phosphorus to sulfur in the product E is 2.87 and in the product F the atomic ratio of phosphorus to sulfur is 1.03. It has been found that the atomic ratio of phosphorus to sulfur is usually between about 1.5 and about 3.0 for materials from long chain olefin hydrocarbons and between about 0.5 and about 1.5 for materials from hydrocarbon fractions. Another factor which may contribute to difierences between the combination of addition agents of this invention and the agents when used alone is due to the fact that different types of organic materials are reacted with a, sulfide of phosphorus in preparing the various addition agents.

The foregoing description and examples of our invention are not to be taken as limiting since many variations may be made by those skilled in the art without departing from the spirit or scope of the following claims.

We claim:

1. A composition of matter adapted for addition to lubricating oil comprising the reaction product obtained by phosphosulfurizing a hydrocarbon lubricatin oil fraction from WhlCh the most highly aromatic and the most highly parafiinic components have been removed, which hydrocarbon lubricating oil fraction is selected from those lubricating oil fractions obtained as a solvent rafiinate of a solvent extract and a solvent extract of a solvent raffinate, said solvent being a selective solvent of the type which selectively dissolves the more aromatic hydr carbons and said selective solvent being chosen from the group consisting of the same solvent used in extract formation and raflinate formation under different conditions of treatment, and a different selective solvent used in extract formation and rafiinate formation, said reaction product being obtained by reacting saidlubricating oil fraction with between about 3% and of a phosphorus sulfide at temperatures between about 200 F. and 600 F.

2. A composition of matter as set forth in claim 1 in which the phosphorus sulfide has an atomic ratio of phosphorus to sulphur ofabout 0.5 to 1.5.

3. A composition of matter as set forth in claim 2 in which the phosphorus. sulfide is phosphorus pentasulfide. I

4. A composition of matter adapted for addition to lubricating oil comprising an oil-soluble metal salt of'the reaction product obtained by phosphosulfurizing a hydrocarbon lubricating oil fraction from which the most highly aromatic and the most highly paraifinic components have been removed, which hydrocarbon lubricating oil fraction is selected from those lubricating oil fractions obtained as a solvent raffinate of a solvent extract and a solvent extract of a solvent raffinate, said solvent being a selective solvent of the type which selectively dissolves the more aro matic hydrocarbons and said selective solvent being chosen from the group consisting of the same solvent used in extract formation and rafiinate formation under different conditions of treatment, and a different selective solvent used in extract formation and raffinate formation, said reaction product being obtained by reacting said lubricating oil fraction with between about 3% and 50% of a phosphorus sulfide at temperatures between 200 F. and 600 F.

5. A composition of matter as set forth in claim 4 in which the phosphorus sulfide has an atomic ratio of phosphorus to sulphur of about 0.5 to 1.5.

6. A composition of matter as set forth in claim 4. in which the phosphorus sulfide is phosphorus pentasulfide.

7. A lubricating oil composition containing a major proportion of mineral lubricating oil and a small amount, sufficient to impart detergency and anti-corrosion properties to said oil, of an oil-soluble metal salt of the reaction product obtained by phosphosulfurizing a hydrocarbon lubricating oil fraction from which the most highly aromatic and the most highly parafiinic components have been removed, which hydrocarbon lubricating oil fraction is selected from those lubricating oil fractions obtained as a solvent rafilnate of a solvent extract and as a solvent extract of a solvent rafiinate, said solvent being a selective solvent of the type which selectively dissolves the more aromatic hydrocarbons and said selective solvent being chosen from the group consisting of the same solvent used in extract formation and rafiinate formation under different conditions of treatment, and a different selective solvent used in extract formation and raflinate formation, said reaction product being obtained by reacting said lubricating oil fraction with between about 3% to 50% of a phosphorus sulfide at temperatures between about 200 F. and 600 F.

8. A composition as set forth in claim 7 in which the phosphorus sulfide has an atomic ratio of phosphorus to sulphur of about 0.5 to 1.5.

'9'. a composition asset fort in claim '1 in which the phosphorus sumac is phosphorus pentasulphide, 7 r

10. A 'oih fibsitibfi as set fdith if! claim 7 which includes a small amount of an oil-soluble detergent. 7 v

11. A composition as set forth in claim 10 in which the detergent is an oil-soluble metal sulfbl'l ate'. V

12, A composition as set forth in claim 7 in which the phosphorus sulfide is phosphorus pentas'ul'fid in amount to impart a phosphorus content to "said on "or hetlivenahout 0.01% and about 0.5% by weight and the hydrocarbon lubricating an fractioh is an jiifiteifmediate fraction of a lutfiatihg an distillate 'binl: obtained by solvent fractionation of alubricatin oil distillate and containingfnotiiiore'than about 20% by volume of :ii iatrial havihgh viscosity gravity constant outside the rangejoj about 'ilfi to 0 .9 5, and in which the coinpositionfincludes between about 0.5% and about 2 5 byjwei ghtpf an oil-soluble salt ofsul'f onic acids obtained by sulfonating an n mediate f actio 1 br c n o distillate obtained by solvent fractionation of a lubricating oildistillate and containing not more than about 20% by volume of material having a viscosity 20 gravity constant outside the range orabcut 0.82 to 0.95.

13. A lubricating composition according to claim 7 containing also a small amount of an oil-soluble phosphorus containing material prepared by reacting a sulfide of phosphorus with 'a long chain olefin hydrocarbon and converting the reaction product to a metal salt.

14. A lubricating composition according to claim 7 containing also a small amount of an oil-soluble phosphorus containing material prepared by reacting a sulfide of phosphorus with a hydrocarbon olefin polymer having a molecular Weight above about 500 and converting the reaction product to a metal salt.

JOHN P. BUCKMANN. LOREN L. NEF'F.

REFERENCES, (HT-il The following referenlces are of record in the file of this patent:

UNITED STATES 'PATENTS 

